Sharing a wireless connection to an "un-wireless" computer.

Is it posssible to share a wireless connection through an airport express and its ethernet connection to a computer that does not have wireless capability?

just to make this more clear, I have an airport express connected to an existing network, and over it I share music and have a printer connected, can I also plug in an ethernet cable and share the internet connection?

Heres another question, say I wanted to share that connection to more than one computer, can I plug that ethernet cable into a router and plug some computers into that? How about two routers with some patch cable?

Heres another question, say I wanted to share that connection to more than one computer, can I plug that ethernet cable into a router and plug some computers into that? How about two routers with some patch cable?

And if I wanted to be able to remote desktop into those computers wirelessly over the network, could I do that?